In Greasemonkey (And Tampermonkey and most userscript engines) a script will fire on an iframe automatically if it meets the @include, @exclude, and/or @match directives. And, a popular question is how to stop Greasemonkey from firing on iframes. So, if your script had a match like: @match https://fiddle.jshell.net/* It would fire on jsFiddle “output” pages … Read more
It is possible when using Tampermonkey or Violentmonkey (Firefox or Chrome). Those userscript managers have added a GM_download method. You can use it like this: // ==UserScript== // @name New Userscript // @namespace http://tampermonkey.net/ // @version 0.1 // @description try to take over the world! // @author You // @match http*://*/* // @grant GM_download // … Read more
Background Doesn’t Greasemonkey inject my extensions JavaScript already? Can someone clarify this for me please. Greasemonkey executes your scripts in a sandbox, which is a restricted environment without direct access to the JavaScript in the page. Earlier versions of Greasemonkey injected scripts directly into the page, but this introduced serious security vulnerabilities. In the old … Read more
In Chrome, most of the ES6 features are hidden behind a flag called “Experimental JavaScript features”. Visit chrome://flags/#enable-javascript-harmony, enable this flag, restart Chrome and you will get many new features. Arrow functions are not yet implemented in V8/Chrome, so this flag won’t “unlock” arrow functions. Since arrow functions are a syntax change, it is not … Read more
For this, just use the CSS cascade. Add a style sheet to the page with GM_addStyle(). Note: We use the !important flag to cover certain potential conflicts. Use @run-at document-start (or use Stylus, see below) to minimize “flicker” associated with changing styles after the initial render. A complete script: // ==UserScript== // @name _Override banner_url … Read more
Send mouse events. Like so: //— Get the first link that has “stackoverflow” in its URL. var targetNode = document.querySelector (“a[href*=’stackoverflow’]”); if (targetNode) { //— Simulate a natural mouse-click sequence. triggerMouseEvent (targetNode, “mouseover”); triggerMouseEvent (targetNode, “mousedown”); triggerMouseEvent (targetNode, “mouseup”); triggerMouseEvent (targetNode, “click”); } else console.log (“*** Target node not found!”); function triggerMouseEvent (node, eventType) { … Read more
Yes, in theory, a site can deduce the presence of scripts in various situations. This is not foolproof and usually is way too much trouble for the negligible “threat” to the site. (Then again, some webmasters can be obsessive-paranoids about such things. 😉 ) Some methods, depending on what the script does (in no particular … Read more
The only way to communicate with the code running on the page in Chrome is through the DOM, so you’ll have to use a hack like inserting a <script> tag with your code. Note that this may prove buggy if your script needs to run before everything else on the page. EDIT: Here’s how the … Read more
You could insert input fields without “name” attribute: <input type=”text” id=”in-between” /> Or you could simply remove them once the form is submitted (in jQuery): $(“form”).submit(function() { $(this).children(‘#in-between’).remove(); });
See “Are Chrome user-scripts separated from the global namespace like Greasemonkey scripts?”. Both Chrome userscripts/content-scripts and Greasemonkey scripts are isolated from the page’s javascript. This is done to help keep you from being hacked, but it also reduces conflicts and unexpected side-effects. However, the methods are different for each browser… Firefox: Runs scripts in an … Read more